The project described in this proposal will 1) develop efficient, cost-effective, methods for predicting the families which produce juvenile delinquents, and 2) explain why such youths become offenders. The present proposal requests funds for a two-year period during which prediction instruments will be selected, developed, and refined. During the two-year planning period a trial run of the full scale project will be carried out on a sample of thirty youths known to be offenders, and thirty youths not meeting the criteria for assignment to the at-risk group. In addition, a second sample of 150 boys, 75 ten-year-olds and 75 fifteen-year-olds will be studied with less intensive measures. The proposed prediction-methodology will be based upon a graded series of selection devices ranging from teachers' ratings to school records to home observation. Each source of information and each level of precision increases the true identification and reduces false identifications. The prediction methodology developed during the planning years will be applied to a second, much larger, sample during the main study period. The main study will follow at-risk and normal youths for nine years following original selection. On the basis of data gathered during the longitudinal project a theory of the origins and development of stealing will be developed.